Multi-ply sound-proofing and thermal insulation part

ABSTRACT

The invention relates to a multilayered acoustic and thermal insulation part ( 1 ), in particular for motor vehicles, with at least one three-dimensionally structured foamed-plastic layer ( 2 ) and at least one nonwoven-fabric layer ( 3 ) lying adjacent thereto, whereby the foamed-plastic layer has a plurality of protrusions ( 4 ) and/or depressions ( 5 ). In order to be able to produce such an insulation part cost-effectively with a low weight, provision is made such that the nonwoven-fabric layer ( 3 ) is needled onto the foamed-plastic layer ( 2 ), and in such a way that the nonwoven-fabric layer lies contour-parallel next to the foamed-plastic layer and the protrusions ( 4 ) and/or depressions ( 5 ) of the foamed-plastic layer ( 2 ) are also impressed in the surface of the nonwoven-fabric layer ( 3 ) facing away therefrom. The jointing of the nonwoven-fabric layer and the foamed-plastic layer of the insulation part is thus produced without adhesive, so that costs on adhesive are saved and the weight of the insulation part is correspondingly reduced.

[0001] The invention relates to a multilayered acoustic and thermal insulation part, in particular for motor vehicles, with at least one three-dimensionally structured foamed-plastic layer and at least one nonwoven-fabric layer lying adjacent thereto, whereby the foamed-plastic layer has a plurality of protrusions and/or depressions.

[0002] Such an acoustic and thermal insulation part is known for example from WO 00/34943 A1. The foamed-plastic layer of the known insulation part consists of polyimide foamed plastic and runs in a zigzag form, whereby hollows spaces roughly V-shaped in cross-section are provided between the foamed-plastic layer and the nonwoven-fabric layer in the wedges of the zigzag shape. The nonwoven-fabric layer is placed on the foamed-plastic layer without gluing, lamination or suchlike. The two layers are held together by an edge-welded enveloping film.

[0003] Furthermore, a heat-insulating and sound-insulating lining for the engine compartment of motor vehicles is described in DE 198 21 532 A1. This lining consists of a cover layer on the engine side, an acoustically insulating duroplastic foamed-plastic layer permanently temperature-resistant up to 180° C. in contact therewith, an insulating layer of plastic foam or fibrous nonwoven fabric in contact therewith, and a cover layer in contact therewith facing away from the engine side. The foamed-plastic layer and the insulating layer of plastic foam or fibrous nonwoven fabric in contact therewith can have grid-like profiling, which for example consists of convex protrusions. The layers of the lining are joined together by adhesive. DE 198 21 532 A1 does not contain a drawing of the described lining.

[0004] The object underlying the present invention was to provide a multilayered acoustic and thermal insulation part of the type mentioned at the outset, which is particularly light and can be produced cost-effectively.

[0005] This object is solved according to the invention by the fact that the nonwoven-fabric layer is needled to the foamed-plastic layer in such a way that the nonwoven-fabric layer lies contour-parallel next to the foamed-plastic layer and the protrusions and/or depressions of the foamed-plastic layer are also impressed in the surface of the nonwoven-fabric layer facing away from the latter.

[0006] The joining of the nonwoven-fabric layer and the foamed-plastic layer of the insulation part according to the invention is thus produced without adhesive, so that costs on adhesive are saved and the weight of the insulation part is correspondingly reduced. As a result of dispensing with adhesive, possibly environmentally hazardous emissions caused by adhesives can also be avoided. Dispensing with adhesives also simplifies the recycling of corresponding insulation parts. In particular, the insulation part according to the invention has a relatively large nonwoven-fabric layer surface, since the nonwoven-fabric layer lies contour-parallel next to the three-dimensionally structured foamed-plastic layer and thus has essentially the same profile as the foamed-plastic layer with a large acoustically effective surface.

[0007] The impression of the surface profile of the foamed-plastic layer in the nonwoven-fabric layer can also be advantageous with respect to the optical effect of the insulation part, if the nonwoven-fabric layer represents the exposed side of the insulation part. The insulation part according to the invention, therefore, can also have in particular a design function.

[0008] The needling of the nonwoven-fabric layer to the foamed-plastic layer can take place mechanically or by means of a water-jet technique.

[0009] The protrusions and/or depressions of the foamed-plastic layer can be arranged regularly or irregularly. Preferably, however, they are arranged essentially uniform, in particular in a grid form. The grid can be designed square, rectangular or rhomb-shaped.

[0010] The foamed-plastic layer preferably consists of open-cell foamed plastic. In order to produce an especially light and difficultly flammable insulation part, the foamed-plastic layer can preferably be produced from melamine-resin foamed plastic.

[0011] The nonwoven-fabric layer can be made from a spun nonwoven fabric or a needle-punched nonwoven fabric. The fibres of the nonwoven-fabric layer can in particular be synthetic fibres. Furthermore, the nonwoven-fabric layer can also be formed from an aluminium-fibre nonwoven fabric.

[0012] An advantageous development of the insulation part according to the invention consists in the fact that the nonwoven-fabric layer is needled to the foamed-plastic layer in the area of depressions and lies unneedled next to the foamed-plastic layer in the area of protrusions. On the one hand, this prevents perforation of the nonwoven-fabric layer in the area of the protrusions, which, depending on the case, may be desirable for the optical appearance of the nonwoven-fabric layer, and on the other hand the separation of the nonwoven-fabric layer and the foamed-plastic layer is facilitated during subsequent recycling of the insulation part.

[0013] The invention will be explained in greater detail below with the aid of a drawing representing several examples of embodiment. The figures show the following:

[0014]FIG. 1 a perspective representation of a section of an insulation part according to the invention;

[0015]FIG. 2 a cross-sectional view of the insulation part according to FIG. 1;

[0016]FIG. 3 a cross-sectional view of an insulation part according to a second example of embodiment of the invention; and

[0017]FIG. 4 a diagrammatic representation of a plant for the production of an insulation part according to the invention.

[0018]FIG. 1 shows the exposed side of a section of an insulation part 1 according to the invention. Insulation part 1 is designed essentially plate-shaped. It is constructed from a three-dimensionally structured foamed-plastic layer 2 and a nonwoven-fabric layer 3 lying adjacent thereto over its whole surface. Foamed-plastic layer 2 has a plurality of nap-shaped protrusions 4 and trough-shaped depressions 5, which are arranged in a grid form. Protrusions 4 and depressions 5 have been produced in foamed-plastic layer 2 for example by profile-cutting and/or compression moulding prior to the laying-on of the nonwoven fabric. The layer thickness of foamed-plastic layer 2, including protrusions 4, lies in the range from approx. 5 to 20 mm. The layer thickness of nonwoven-fabric layer 3 can for example amount to 1 to 5 mm.

[0019] In this form of embodiment, foamed-plastic layer 2 is structured on one side only, i.e. the opposite side of foamed-plastic layer 2 is essentially even. If need be, however, foamed-plastic layer 2 can also be profiled on both sides and also be provided on the underside with a further plastic or textile layer (see FIG. 3) and/or a plastic or metal foil (not shown).

[0020] As shown diagrammatically in FIG. 2, nonwoven-fabric layer 3 is needled to foamed-plastic layer 2, so that it lies contour-parallel next to foamed-plastic layer 2. Protrusions 4 and depressions 5 of foamed-plastic layer 2 are thus also impressed in the surface of nonwoven-fabric layer 3. The jointing of nonwoven-fabric layer 3 and foamed-plastic layer 2 thus takes place without adhesive.

[0021] The needling of nonwoven-fabric layer 3 to foamed-plastic layer 2 can be carried out by means of a needle beam capable of being raised and lowered, said needle beam having a plurality of needles aligned parallel to one another. Alternatively, the needling of nonwoven-fabric layer 3 can also take place by means of a water-jet technique, i.e. with a plurality of fine high-pressure water jets. The needles or water jets pull a plurality of fibres 6 of nonwoven-fabric layer 3 into foamed-plastic layer 2, so that sections of these fibres 6 are sufficiently firmly dug or anchored in the foamed-plastic layer. A plurality of fibres 6 extend to the underside of foamed-plastic layer 2. On the other hand, sections of these fibres 6 remain dug or anchored in non-woven-fabric layer 3.

[0022] In the example of embodiment represented, nonwoven-fabric layer 3 is essentially uniform and needled over its whole surface to foamed-plastic layer 2. The needling can however also take place in such a way that nonwoven-fabric layer 3 is needled only in the area of depressions 5 and lies unneedled next to foamed-plastic layer 2 in the area of protrusions 4.

[0023] Foamed-plastic layer 2 is preferably made from open-cell foamed plastic, for example from melamine-resin foamed plastic. It is however also possible to use an essentially closed-cell foamed plastic for foamed-plastic layer 2.

[0024] The example of embodiment shown in FIG. 3 differs from that in FIG. 2 firstly by the fact that foamed-plastic layer 2 is three-dimensionally structured on both sides. The structuring consists, on both sides of foamed-plastic layer 2, of a plurality of nap-shaped protrusions 4 and trough-shaped depressions 5, which in turn are arranged in a grid form. It should be noted that a protrusion 4 on one side of foamed-plastic layer 2 lies in each case opposite a depression 5 on the opposite side, and vice versa.

[0025] Furthermore, the example of embodiment in FIG. 3 differs from that in FIG. 2 by the fact that profiled foamed-plastic layer 2 is provided on both sides with a nonwoven-fabric layer 3, 3′. Second nonwoven-fabric layer 3′ is also needled onto foamed-plastic layer 2 in such way that it lies contour-parallel next to foamed-plastic layer 2. Protrusions 4 and depressions 5 of foamed-plastic layer 2 that are facing it are therefore clearly impressed in its surface. The two nonwoven-fabric layers 3, 3′ can be formed from different nonwoven-fabric material.

[0026] Insulation part 1 according to the invention is suitable in particular for the acoustic-insulation and thermal-insulation lining of internal surfaces in motor vehicles.

[0027] Nonwoven-fabric layers 3, 3′ are preferably formed from a spun nonwoven fabric, needle-punched nonwoven fabric and/or aluminium-fibre nonwoven fabric.

[0028] The use of an aluminium-fibre nonwoven fabric is particularly advantageous when insulation part 1 according to the invention is to be used as an acoustically effective heat shield. The aluminium-fibre nonwoven fabric has in particular a heat-reflecting effect. In this case, foamed-plastic layer 2 can, to advantage, be made from melamine-resin foamed plastic, which as is known has a relatively high temperature resistance.

[0029]FIG. 4 is a diagrammatic representation of a plant for the production of an insulation part according to the invention. The foamed-plastic layer designated by 2 is present in the form of a material web, which is first conveyed into a station 7 in which foamed-plastic layer 2 is profiled three-dimensionally at least on one side by contour-cutting and/or compression moulding.

[0030] A nonwoven-fabric layer 3, 3′ is placed respectively on the profiled surface of foamed-plastic layer 2. Nonwoven-fabric layer 3, 3′ can also be present as a material web and be fed from a supply roll. Material webs 2, 3, 3′ brought together then pass through a needling station, which is formed here for example by two needle beams 8, 9 capable of being raised and lowered. Needle beams 8, 9 lying opposite one another are preloaded by means of springs (not shown) or suchlike, so that they maintain a specified distance orthogonal to material webs 2, 3, 3′ brought together. There is assigned respectively to needle beams 8, 9 a cam drive 10, 11, which moves the respective needle beam against the action of the spring towards the material webs, so that the needles of the respective needle beam 8, 9 stick in a cyclical manner into nonwoven-fabric layer 3 and 3′ respectively and foamed-plastic layer 2 and join respective nonwoven-fabric layer 3, 3′ with foamed-plastic layer 2. Instead of mechanical needling by means of needle beams, however, hydraulic needling by means of water jets or suchlike can also be employed. The composite of foamed-plastic layer 2 and nonwoven-fabric layer 3 or nonwoven-fabric layers 3, 3′ produced by the needling is finally wound up into the form of a roll for transport to a further processing station, for example a cutting station for the preparation of specific cuts. It goes without saying that the composite can however also be further processed, in particular cut to size, immediately after the needling station.

[0031] The execution of the invention is not restricted to the example of embodiment described above. On the contrary, a number of variants are possible that even in a fundamentally divergent configuration make use of the inventive idea defined in the claims. 

1. A multilayered acoustic and thermal insulation part (1), in particular for motor vehicles, with at least one three-dimensionally structured foamed-plastic layer (2) and at least one nonwoven-fabric layer (3, 3′) lying adjacent thereto, whereby the foamed-plastic layer (2) has a plurality of protrusions (4) and/or depressions (5), wherein the nonwoven-fabric layer (3, 3′) is needled to the foamed-plastic layer (2) in such a way that the nonwoven-fabric layer (3, 3′) lies contour-parallel next to the foamed-plastic layer (2) and the protrusions (4) and/or depressions (5) of the foamed-plastic layer (2) are also impressed in the surface of the nonwoven-fabric layer (3, 3′) facing away therefrom.
 2. The acoustic and thermal insulation part according to claim 1, wherein the protrusions (4) and/or depressions (5) are arranged in grid form.
 3. The acoustic and thermal insulation part according to claim 1, wherein the protrusions (4) and/or depressions (5) are formed by profile-cutting and/or compression moulding.
 4. The acoustic and thermal insulation part according to claim 1, wherein the nonwoven-fabric layer (3) is joined with the foamed-plastic layer (2) without adhesive.
 5. The acoustic and thermal insulation part according to claim 1, wherein the foamed-plastic layer (2) is produced from open-cell foamed plastic.
 6. The acoustic and thermal insulation part according to claim 1, wherein the foamed-plastic layer (2) is produced from melamine-resin foamed plastic.
 7. The acoustic and thermal insulation part according to claim 1, wherein the nonwoven-fabric layer (3, 3′) is made from a spun nonwoven fabric, needle-punched nonwoven fabric and/or aluminium-fibre nonwoven fabric.
 8. The acoustic and thermal insulation part according to claim 1, whereby the foamed-plastic layer (2) has a large number of protrusions (4) and depressions (5), wherein the nonwoven-fabric layer (3, 3′) is needled to the foamed-plastic layer (2) in the area of the depressions (5) and lies unneedled next to the foamed-plastic layer (2) in the area of the protrusions (4).
 9. The acoustic and thermal insulation part according to claim 1, wherein the foamed-plastic layer (2) is three-dimensionally structured on both sides.
 10. The acoustic and thermal insulation part according to claim 1, wherein the foamed-plastic layer (2) is provided on both sides with a nonwoven-fabric layer (3, 3′).
 11. The acoustic and thermal insulation part according to claim 9, wherein the foamed-plastic layer (2) has on both sides a large number of protrusions (4) and depressions (5) and also the second nonwoven-fabric layer (3′) is needled to the foamed-plastic layer (2) in such a way that it lies contour-parallel next to the foamed-plastic layer (2) and the protrusions (4) and/or depressions (5) of the foamed-plastic layer (2) facing it are impressed in its surface. 